Fiber

Question 1

Cellulose

Answer 1

polymer of linked glucose units
water insoluble; relatively non-fermentable
can be chemically modified to be more soluble and more fermentable by gut microbiota

sources: whole grans, bran, legumes, peas, nuts, root vegetables, cabbage, seeds, apples

Question 2

Hemicellulose

Answer 2

heterogeneous groups of polysaccharides
sugars in backbone and side chain
-xylose, mannose, galactose (backbone)
-arabinose, glucoronic acid, galactose (side chain)

sources: whole grain, nuts, legumes, some vegetables and fruits

Question 3

Pectin

Answer 3

Heterogenous polysaccharides (found in plant cell walls, intercellular region of plants and outer skin and rind of some furits and vegeables)
-backbone = galacturonic acid
-water-soluble and gel forming
-fermented by gut microbiota
-functional: extracted from citrus peels and added to product
sources: apples, berries, apricots, citrus, legumes, some vegetables

Question 4

Lignin

Answer 4

highly branched polymer of phenol units with strong binding
-insoluble in water
-non-fermentable
-has hydrophobic binding capacity
Sources: wheat, rye, mature root vegetables, fruits with edible seeds

Question 5

Gums

Answer 5

Group of substances secreted at site of plant injury
Composed of sugar and derivatives
food additives and thickening agents
-dietary and functional
-fermented by gut

Sources; oatmeal, barley, legume

Question 6

B-glucans

Answer 6

homopolymers of glucose units
-smaller in size than cellulose
-water soluble and highly fermentable
-form viscous gels with digestive tracts
Sources: oats and barley

Question 7

Fructans

Answer 7

Inulin, oligofructose and fructooligosaccharides
-fructose units in chains of varying length
-water soluble and highly fermentable
-Inulin can be used to replace fat
-Sources: chicory, asparagus, leeks, onion, garlic, artichokes, banana

Question 8

Resistant starch

Answer 8

Starch that cannot be digested or absorbed by humans due to its tight packaging and inaccessibility to enzymes

Question 9

Types of resistant starch

Answer 9

RS1: plant cell walls
RS2: ungelatinized starch granules
RS3: retrograde starch from cooking and cooling or extruding foods
RS4: chemically modified starch

RS1 and RS2: dietary fiber
RS3 and RS4: functional fiber

Question 10

Mucilages

Answer 10

Plant polysaccharides with a similar structure to gums
-found in seeds of variety of plants )flax and psyllium)
-high water binding capacity and form viscous gells
-used as a laxities

Question 11

Polydexterose

Answer 11

polysaccharide of glucose and sorbitol units that have been polymerized at high temperatures under parietal vacuum-
used as a bulking agent or sugar substitute

Question 12

polyols

Answer 12

polyglycitol, sorbitol, malitol
found in syrup, mind and gums
-hydrogenated carbs, can be found in nature, absorb water
-partially fermentable and prebiotic

Question 13

Resistant dextrins

Answer 13

resistant maltodextrins
-generated by heating and enzymatically treating starch with amylase
-glucose polymers containing a variety of glucosidic bonds
-wheat dextrin water soluble and fermentable by colonic bacteria
-designated as functional fiber

Question 14

Chitin and chitosan

Answer 14

Chitin
-straight chain polymer containing b1-4 linked glucose units
-component of exosceleton of insects

Chitosan
-deacetylated from chitin
-both insoluble in water and can interact with dietary lipids
functional

Question 15

soluble fibers

Answer 15

Short Chain: fructooligosacchrides, galactooligosaccharides
Long Chain: pectin, gums, inulin, resistant starch, wheat dextrin
Intermediately soluble: psylium, b-glucans, some hemicelluloses and pectin